1. Field of the Invention
This invention relates to the mechanical arts. In particular, this invention relates to a blowout latch for securing an aircraft panel to an aircraft structure.
2. Discussion of the Related Art
A blowout latch automatically opens when the pressure inside of a panel, to which the blowout latch is mounted, exceeds a predetermined amount. Modern aircraft employ many types of latches, including blowout latches, to secure aircraft panels to adjacent aircraft structures. For example, blowout latches are used to secure the panels enclosing the aircraft""s engine. When used in such an environment, the blowout latch opens and relieves pressure that builds up inside of the panels due to the jet exhaust stream flowing through the jet engine. The opening ofthe blowout latch allows the panels to pivot open thus preventing any damage due to excessive loads on the panels and other structural components.
One such blowout latch is disclosed in U.S. Pat. No. 5,765,883. The latch includes a bolt that is pivotally mounted to a housing connected to the aircraft panel. The bolt has a slot into which a screwdriver is inserted for manually releasing the latch. Another blowout latch, disclosed in U.S. Pat. No. 3,571,977, also requires a screw driver or other tool be inserted into a slot in the bolt in order to manually open the latch. Accordingly, these latches disadvantageously require a separate tool for manual opening required for routine maintenance and inspection.
Another characteristic of both latches is that when the latch is open, the portion of the bolt that extends above the surface of the housing is small. Thus, the bolt cannot be used as an immediately visible indicator that the latch is open. Therefore, observers from the ground may not be alerted that the latch is open and not properly closed and secured. Therefore, a further disadvantage of the latches is that they do not provide an immediately visible indicator that the latch is open. These latches and other conventional blowout latches have the added disadvantage of being large and heavy, weighing five pounds or more.
In view of the above, it should be appreciated that there is a need for a blowout latch that does not require a separate tool for opening the latch, that is easy to open for maintenance and inspection, that provides an indicator visible from the ground when the blowout latch is not closed and secured, and that is compact and lightweight.
The invention resides in a blowout latch that provides advantages over known latches in that the blowout latch does not require a separate tool for opening. Also, the blowout latch is easy to open for maintenance and inspection. Furthermore, the blowout latch provides an indicator that is visible from the ground when the blowout latch is not closed and secured. In addition, the blowout latch is compact and lightweight.
The blowout latch is used to releasably secure an aircraft panel to an aircraft structure. The blowout latch includes a housing, a bolt, and a handle. The housing includes a bias section that has a plate, a block, at least one coil spring having opposing ends, a roller mount, and a roller pin. The block is positioned adjacent to the plate. The roller mount has a roller mount base. One end of the coil spring contacts the roller mount base. The opposing end of the coil spring contacts the block. The roller pin is rotatably mounted to the roller mount. The bolt is rotatably mounted to the housing and engages the aircraft structure. The bolt has a secured position. The bolt is held in its secured position by the coil spring biasing the roller pin against the bolt. The handle is rotatably mounted to the bolt and is moveable between a latched position and an unlatched position, without the use of a tool. The handle provides an indicator when the blowout latch is in an open position. In other embodiments of the present invention, the bolt includes a detent notch.
Other embodiments of the present invention include a handle spring which interfaces with the handle and bolt. The handle spring urges the handle toward the unlatched position. Further embodiments of the present invention include; a trigger lock that is pivotally mounted to the handle and secures the handle to the bolt, and a handle with a handle base plate and a trigger spring. The trigger spring interfaces with the trigger lock and the handle and urges the trigger lock toward a flush position relative to the handle base plate. In another embodiment of the present invention, the housing includes a faceplate having recessed channel. The recessed channel receives the handle when the handle is in its latched position.
Another embodiment of the present invention includes an adjustment screw that is threadably mounted through the plate. The adjustment screw is used to vary the length of the coil spring by adjusting the position of the block relative to the roller mount base. A compression of the length of the coil spring increases the force applied by the roller pin on the bolt. In contrast, an expansion of the length of the coil spring decreases the force applied by the roller pin on the bolt.
Embodiments of the present invention include coil springs that apply a force of at least about 400 pounds and a total weight for the blowout latch that is less than 1.4 pounds.
One feature of the present invention is that the handle eliminates the need for a separate tool, such as a screw driver, when manually opening the blowout latch. Additionally, the handle provides for ease of opening the blowout latch for maintenance and inspection. Another feature of the present invention is that the handle extends above the aircraft panel when the blowout latch is open. The position of the handle above the aircraft panel advantageously provides an indicator to observers on the ground that the blowout latch is not closed and secured. A further feature of the present invention is that the blowout latch provides at least 400 pounds of force for securing the bolt in the latched position while remaining compact and light, weighing approximately 1.3 pounds.
Other features and advantages of the present invention will be set forth, in part, in the description which follows and the accompanying drawings, wherein the preferred embodiments of the present invention are described and shown, and in part will become apparent to those skilled in the art upon examination of the following detailed description taken in conjunction with the accompanying drawings, or may be learned by practice of the present invention. The advantages of the present invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.